icl3237e Intersil Corporation, icl3237e Datasheet - Page 8

• Manufacturer Part Number: icl3237e
• Description: ?15kv Esd Protected, 1?a Supply-current, +3v To +5.5v, 250kbps Or 1000kbps, Rs-232 Transmitters/receivers
• Manufacturer: Intersil Corporation

Operation Down to 2.7V
ICL3237E transmitter outputs meet RS-562 levels (
the full data rate, with V
typically ensure inter operability with RS-232 devices.
Transmitter Outputs when Exiting
Powerdown
Figure 4 shows the response of two transmitter outputs
when exiting powerdown mode. As they activate, the two
transmitter outputs properly go to opposite RS-232 levels,
with no glitching, ringing, nor undesirable transients. Each
transmitter is loaded with 3kΩ in parallel with 2500pF. Note
that the transmitters enable only when the magnitude of the
supplies exceed approximately 3V.
High Data Rates
The ICL3237E maintains the RS-232
transmitter output voltages even at high data rates. Figure 5
details a transmitter loopback test circuit, and Figure 6
illustrates the standard speed loopback test result for a
single transmitter driving 1000pF and an RS-232 load at
250kbps. Figure 7 shows the MegaBaud loopback results for
a single transmitter driving 250pF and an RS-232 load at
1Mbps. The static transmitters were also loaded with an
RS-232 receiver.
5V/DIV
2V/DIV
FIGURE 4. TRANSMITTER OUTPUTS WHEN EXITING
V
C1 - C4 = 0.1µF
CC
= +3.3V
POWERDOWN
SHDN
CC
TIME (20µs/DIV.)
as low as 2.7V. RS-562 levels
8
±
5V minimum
±
T1
T2
3.7V), at
ICL3237E
5V/DIV.
5V/DIV.
R1
R1
T1
T1
FIGURE 6. LOOPBACK TEST AT 250kbps (C
T1
T1
OUT
OUT
OUT
OUT
FIGURE 5. TRANSMITTER LOOPBACK TEST CIRCUIT
FIGURE 7. LOOPBACK TEST AT 1Mbps (C
IN
IN
V
V
C
C
CC
CC
1
2
MBAUD = GND
MBAUD = V
V
C1 - C4 = 0.1µF
V
C1 - C4 = 0.1µF
+
+
CC
CC
= +3.3V
= +3.3V
0.1µF
CC
C1+
C1-
C2+
C2-
T
R
EN
SHDN
IN
OUT
+
ICL3237E
V
CC
0.5µs/DIV.
2µs/DIV.
T
MBAUD
OUT
R
V+
5k
V-
IN
L
L
= 250pF)
= 1000pF)
GND or V
+
+
C
C
C
3
4
L
CC